1. Field
The present disclosure relates to a fuel cell stack.
2. Description of the Related Art
For example, a solid polymer electrolyte fuel cell includes a membrane electrode assembly (MEA), in which an anode electrode is disposed on one side of an electrolyte membrane and a cathode electrode is disposed on the other side of the electrolyte membrane. The electrolyte membrane is made from a polymer ion-exchange membrane. The MEA and a pair of separators, sandwiching the MEA therebetween, constitute a power generation cell. Typically, a predetermined number of such power generation cells are stacked and used, for example, as a vehicle fuel cell stack.
Particularly when used in a vehicle, a fuel cell stack may be subjected to a shock, vibration, an external load, and the like. Therefore, a structure in which a fuel cell stack is disposed in a box is used in order to provide rigidity to the entirety of the fuel cell stack. As an example of this type of structure, Japanese Unexamined Patent Application Publication No. 2008-112708 describes a fuel cell stack fastening structure.
As illustrated in FIG. 6, in this fastening structure, end plates 2b and 2a are closely attached to upper and lower end surfaces of a separator 1. A pair of angular-U-shaped enclosure panels 3a and 3b, which are detachable, cover four of the peripheral surfaces of the separator 1, except for the upper and lower end surfaces. In the detachable fastening structure, recesses, which are formed concavely along peripheral side surfaces of the end plates 2a and 2b, and projections, which are formed on upper and lower edge portions of the enclosure panels 3a and 3b, are fitted to each other.